Not necessarily. All mattresses require a supportive base, but that support can come from a foundation or a traditional boxspring, depending on what kind of bed frame you’re using with it.
The one exception is the Saatva HD which requires pairing with the Saatva HD foundation. This HD foundation is 4.75″ high.

Saatva mattresses do not require a boxspring if:
- The mattress support system you have is less than 7 years old.
- Your existing foundation is in good condition.
- You have a slat foundation with slats less than 4″ apart.
- You have a platform bed (no foundation required).
- You have an adjustable base (no foundation required).